Within many industries today, removal of volatile organic compounds (VOCs) from gases is a worldwide priority due to their health risks and harmful effects on the environment. In particular, organizations such as the Environmental Protection Agency have placed strict limits on the emission of certain classes of VOCs, including BTX (benzene, toluene, xylene), BTEX (benzene, toluene, ethylbenzene, and xylene), BTEXN (benzene, toluene, ethylbenzene, xylene, and naphthalene), and TEXS (benzene, toluene, ethylbenzene, xylene, and styrene). However, separation and capture of such VOCs remain some of the most intensive and challenging industrial separations. Further, the presence of VOCs in gasses frustrates many industrial processes. For example, amine scrubbing is a common process used to remove acid gases such as CO2 and H2S from raw gas, but the amine process solution is easily contaminated by VOCs such as BTX and BTEX present within the gas.
Solid, porous material systems are a developing class of materials that have potential to solve or alleviate many technical problems generally germane to gas capture. Zeolite materials have long been used in many gas capture applications, but suffer from limited gas selectivity and cyclic adsorption performance in the presence of moisture. Metal organic frameworks (MOFs) are a new class of material which generally include porous crystals assembled from modular molecular building blocks, and provide a wide array of advantageous material properties including high surface area, porosity, and sorption potential. While the available building block options, and combinations thereof, are virtually limitless, such potential highlights the statistical difficulty in identifying and assembling MOFs with desired and particularized material properties and multi-faceted functionality. For example, many MOFs exhibit high selectivity towards a particular molecular species, but are highly intolerant to water.